The Northern Ireland international, who earned 85 caps, was released by Kilmarnock at the start of this year for disciplinary reasons.
Prior to that he was handed a 10-game SFA ban for using sectarian language last October.
Lafferty went onto join Linfield after his exit from Scotland, but failed to score in eight matches and was not offered an extension on his short-term deal.
The 35-year-old had won three league titles between 2008-11 at Rangers, plus a Scottish Cup and two League Cup titles.
He was also part of the Kilmarnock side that won the Championship in 2021-22 season, and has played for 15 different clubs over his 18 year career including Burnley, Norwich City, Hearts and Sunderland.
Johnstone Burgh also signed former Scotland midfielder Graham Dorrans at the end of last season.
